The present invention relates, generally, to methods and apparatus for shipping bulk liquids, near-liquids or dry particulate materials in a flexible inner tank within a steel container and specifically, to methods and apparatus providing a liner between the inner tank and the interior walls of the steel container which not only provides some protection against moisture and chemical degradation, but which also adds mechanical and fluid stability around the exterior of the flexible inner tank to prevent the rolling and sloshing of the materials within the flexible inner tank.
It is well recognized in the shipping art that it is generally desirable to ship pumpable materials in bulk containers, both as to the economies of scale and as to the handling and distribution of the shipping containers.
The prior art has produced various liners for shipping materials. For example, U.S. Pat. No. 5,506,020 to Haberkorn shows an insulating freight container quilt including components of spun-bonded polypropylene and polyester which may be placed over articles in a truck.
U.S. Pat. No. 5,143,245 to Malone discloses a thick bag of air cell polyethylene wrapper around cargo placed in a shipping container.
U.S. Pat. No. 5,027,946 to Parsons shows an insulating sheet wrap for a bundle of shingles.
U.S. Pat. No. 5,312,162 to Baebel discloses a plurality of sheets placed within a transport vehicle to facilitate the removal of a powder or particulate load from the vehicle.
U.S. Pat. No. 5,687,517 to Wiercinski, et al., discloses a corrugated polypropylene and/or polyethylene laminate for use in a roofing environment.
U.S. Pat. No. 3,684,642 to Rogers shows a corrugated polypropylene film intended for the packing industry.
U.S. Pat. No. 5,102,036 to Orr et al., shows a corrugated insulated wrap, constructed of paper.
U.S. Pat. No. 4,282,279 to Strickland is illustrative of many patents showing insulating sheets in wrapped proximity to various articles.
U.S. Pat. No. 4,457,986 to Barris et al., and U.S. Pat. No. 3,752,354 to Demirag, each discloses flexible bladders for liquid products positioned within a rigid enclosure.
U.S. Pat. No. 5,518,171 to Moss shows corrugated plastic sheets having slots for connecting together.
U.S. Pat. No. 5,766,395 to Bainbridge et al., discloses a wood fiber-filled polypropylene sheet sand a corrugated paperboard medium.
The prior art has attempted to both protect the inner liner and to make the system impervious to invasion by moisture and chemicals using other methods and apparatus. For example, it is known with intermediate bulk containers (xe2x80x9cIBCxe2x80x9d), to use a corrugated paperboard (or cardboard) liner around the flexible bladder, and then to surround the corrugated liner with a plastic wrap in an attempt to keep the corrugated liner from being exposed to moisture. Exposure to moisture or chemicals would, in most cases, destroy the paperboard liner.
It is also known in the prior art to merely make the flexible bladder itself stronger, thicker and resistant to moisture, without using any liner external to the bladder. These attempts involve heavy duty rubberized bladders which, while having limited success, cannot often be used with food grade materials because of the materials absorbing the odor from the rubberized bladder itself.
The prior art also has included a foldable blanket apparatus having a liner around the flexible bladder having a flexible polyester coated fabric outer liner with a multi-layered, flexible disposable inner liner which, while providing some protection to the bladder from moisture and chemicals, offers no mechanical support to prevent hurling and sloshing of the fluid, and which are quite expensive, requiring that the liners be shipped back to the point of origin. Such liners are available from Crestbury Limited, Hempstead Road, Holt, Norfolk NR 25 6DL England, under their Multibulk trademark.
The prior art has also recognized the problem of shipping fluids through reduced temperature regions of the world. For example, when shipping corn syrup, the syrup usually must be heated before the syrup can be pumped out of the container. In U.S. Pat. No. 302,017 to E.L. Orcutt, especially in FIG. 4, a steam jacket is placed around the bottom of a kettle A to cause the sugar syrup to flow easily.
In U.S. Pat. No. 1,562,991 to E. A. Rudigier, a railway tank car is equipped with tubes running through the interior of the tank through which steam or other heating fluid can be supplied to heat the transported material and facilitate the unloading of the transported material.
In U.S. Pat. No. 3,945,534 to E. W. Ady, there is a disclosure of a flexible bag containing an unidentified food, and having a bag containing a processing fluid 24 for heating the food within the container.
U.S. Pat. No. 3,583,415 to V. D. Smith shows a plurality of corn syrup tanks equipped with a heat exchanger and hot water tubes both within and around tube 88 carrying the corn syrup, to heat the syrup and thus allow the continuous flow of the liquid syrup.
U.S. Pat. No. 4,454,945 to S. A. Jabarin et al., shows a flexible bag 21 transported within a crate or box, but containing no method or apparatus for heating the contents within the flexible bag.
The prior art also includes stainless steel or carbon steel tanks, transportable by tractor-trailer trucks or the like, having steam channels on the lower half of the tanks, and on some designs, around the circumference. Such tanks, sometimes knows as xe2x80x9cISOTANKSxe2x80x9d, are widely available, for example, from Twinstar Leasing, Ltd., located at 1700 One Riverway, Houston, Tex. 77056.
U.S. Pat. No. 5,884,814 to Charles M. Nelson, describes a system for heating the materials in flexible bladders to ensure the pumpability of the materials out of the bladders at the final destination. The teaching of U.S. Pat. No. 5,884,814 is incorporated herein by reference but is, for the most part, repeated hereinafter to facilitate the understanding of the present invention.
The prior art has failed, however, to provide a system in which a large flexible bladder, designed to hold on the order of 40,000 pounds of pumpable material, can be transported in a 20xe2x80x2 long steel shipping container, and yet be protected to a degree from moisture and chemicals, and be protected from hurling and sloshing of the huge volume of pumpable material, which otherwise can bring about the destruction of the bladder and the catastrophic leaking of the materials shipped.
It is therefore the primary object of the present invention to provide methods and apparatus involving the use of new and improved external liners for flexible bladders at least partially filled with liquid materials.
It is also an object of the present invention to provide methods and apparatus involving the use of new and improved external liners for flexible bladders at least partially filled with partially frozen liquid materials.
It is yet another object of the present invention to provide methods and apparatus involving the use of new and improved external liners for flexible bladders at least partially filled with dry, granulated or powdered materials.
These and other objective features and advantages of the present invention will become apparent from a reading of the following detailed description of the invention, taken in conjunction with the accompanying drawings.